Preparation Of Heteroatom-doped Carbon Materials And Their Electrocatalytic Performances Of Oxygen Reduction Reaction For H₂O₂ Generation

Hydrogen peroxide（H₂O₂）,as a crucial chemical,plays a crucial role within the fields of business,setting and energy.At present,the most process of commercial production of peroxide is that the anthraquinone method,which needs an outsized quantity of energy and valuable catalysts to participate within the reaction,and has bound safety issues.The electrocatalytic two-electron oxygen reduction reaction（ORR）provides a method for in-situ production of hydrogen peroxide,which is more energy-efficient and environmental-friendly.Catalyst materials are the key to this method.Commonly used precious metal catalysts limit their applications due to their scarcity.This article mainly explores non-precious metal catalysts（carbon materials and composite materials）catalyzing the two-electron ORR reaction and the optimization of its catalytic performance.Synthesis and optimization of metal（Mn）composite carbon material Mn-N-C:We polymerize transition metal Mn and aniline in situ and obtain Mn-N-C catalyst material by high temperature treatment in N₂ atmosphere.Mn-N-C-800 under the best optimized conditions shows excellent electrocatalytic performance:the selectivity of H₂O₂ can reach 84%under alkaline conditions;the highest yield can reach 335 mg·L^-1·h^-1 under the applied potential of 0.35 V（vs RHE）,Faraday efficiency is above 85%;in the two-electrode method test,when the applied potential is 2.4 V（cell potential）,the yield of H₂O₂ reaches 268.9 mg·L^-1·h^-1.The Faraday efficiency is as high as 96.8%.Based on the material characterization and test results,we deduce that the co-doping of Mn,N,and O elements may be beneficial to improve the electrochemical performance of carbon materials in the two-electron ORR reaction.We used cattail plants as carbon sources,prepared carbon materials through hydrothermal reaction and high temperature calcination;took microwave processing methods to process and optimize the materials.The optimized material shows high H₂O₂ selectivity and activity.Under alkaline conditions,the selectivity of H₂O₂ is as high as 85%.Under the potential of 0.25 V vs RHE,the yield of H₂O₂ reaches 485mg·L^-1·h^-1.Combined with the material characterization and analysis we deduced that microwave treatment not only altered the oxygen content in the material,but also made the material surface more small particles（functional group）,which could be reactive sites.